1. Field of the Invention
The present invention relates to plug-in terminals, and in particular to a terminal for gripping and positioning a stripped end of a stranded insulated conductor in proximity with a conductive path on a circuit board for being soldered thereto, wherein the extremity of the stripped end is loosely gripped by a section of the terminal to allow passage of the solder within the section and around the strands.
2. Description of the Prior Art
In the manufacture of electronic equipment, connections between solderable conductive paths on a circuit board and stranded insulated conductors are often accomplished through the use of wire connectors or terminals. A stripped end of the conductor is crimped within an elongated, plug-in terminal, with a first end of the terminal tightly gripping the strands along the stripped end and with a second and opposite end of the terminal gripping the insulation adjacent the stripped end. The terminal is then extended through a hole in the circuit board which passes through, and is surrounded by, the conductive path, to position the first end of the terminal slightly beyond the path. A glob of molten solder is then deposited over the first end of the terminal and the conductive path to effect an electrical connection, through the body of the terminal and the solder, between the conductor and the path, and to secure the terminal to the path and within the hole in the circuit board.
With conventional plug-in terminals, the strands are either completely encased within or tightly gripped by the terminal at the extremity of the stripped end, which precludes the deposited solder from readily entering within the terminal and around and between the strands therewithin. Therefore, the structural and electrical bond established by the solder exists only between the conductive path, the solder, and the outside body of the terminal at the first end thereof.
The conductive path on a circuit board is immobile and, accordingly, a connection made thereto with solder generally remains secure. The terminal, however, is subject to forces and strains exerted thereon by movement of the conductor as well as by flexing of the circuit board. These forces and strains may, and often do, destroy the electrical and metallurgical bond between the terminal and the solder which, of course, destroys the electrical connection between the conductor and the conductive path on the circuit board. Ordinarily, the application of solder over the terminal and the conductive path is accomplished by passing the circuit board over a solder wave, which is an economical operation. Repair of one or more destroyed connections, however, requires troubleshooting by a technician to first locate the bad connections, and then manual resoldering thereof, both of which are time consuming operations, and therefore expensive.
Another problem encountered with conventional plugin terminals is in extending the terminals through the circuit board to project a predetermined distance beyond the conductive path, and in preventing withdrawal of the terminals from the circuit board prior to the soldering thereof. Projection of the terminals beyond the path by less than a predetermined distance may result in a weak and inadequate solder connection between the terminals and the path, or possibly in no connection at all. Projection of the terminals beyond the path by more than the predetermined distance may require manual trimming or machining of the ends of the terminals to prevent accidental shorting between circuit boards which are in a closely spaced, side-by-side relationship. And, of course, withdrawal of terminals from the circuit board prior to soldering thereof requires operator reinsertion.